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New Tractable Cases in Default Reasoning from Conditional Knowledge Bases

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Logics in Artificial Intelligence (JELIA 2000)

Part of the book series: Lecture Notes in Computer Science ((LNAI,volume 1919))

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Abstract

We present new tractable cases for default reasoning from conditional knowledge bases. In detail, we introduce q-Horn conditional knowledge bases, which allow for a limited use of disjunction.We show that previous tractability results for ε-entailment, proper ε-entailment, and z- and z +-entailment in the Horn case can be extended to the q-Horn case. Moreover, we present feedback-free- Horn conditional knowledge bases, which constitute a new, meaningful class of conditional knowledge bases. We show that the maximum entropy approach and lexicographic entailment are tractable in the feedback-free-Horn case. Our results complement and extend previous results, and contribute in refining the tractability/ intractability frontier of default reasoning from conditional knowledge bases.

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Authors and Affiliations

  1. Institut und Ludwig Wittgenstein Labor für Informationssysteme, TU Wien, Favoritenstraβe 9-11, A-1040, Wien, Austria

    Thomas Eiter & Thomas Lukasiewicz

Authors
  1. Thomas Eiter
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  2. Thomas Lukasiewicz
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Editors and Affiliations

  1. Department of Applied Mathematics, E.T.S.I. Informática, University of Málaga, 29071, Málaga, Spain

    Manuel Ojeda-Aciego  & Inma P. de Guzmán  & 

  2. Intelligent Systems Department, Computer Science Institute, University of Leipzig, Augustusplatz 10-11, 04109, Leipzig, Germany

    Gerhard Brewka

  3. Center for Artificial Intelligence, Department of Computer Science, University of Lisbon, 2825-114, Caparica, Portugal

    Luís Moniz Pereira

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© 2000 Springer-Verlag Berlin Heidelberg

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Eiter, T., Lukasiewicz, T. (2000). New Tractable Cases in Default Reasoning from Conditional Knowledge Bases. In: Ojeda-Aciego, M., de Guzmán, I.P., Brewka, G., Moniz Pereira, L. (eds) Logics in Artificial Intelligence. JELIA 2000. Lecture Notes in Computer Science(), vol 1919. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-40006-0_22

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  • DOI: https://doi.org/10.1007/3-540-40006-0_22

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  • Print ISBN: 978-3-540-41131-4

  • Online ISBN: 978-3-540-40006-6

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